Catheter shaft and associated devices, systems, and methods

ABSTRACT

Systems, devices, and methods for detaching an implantable device from a delivery system are disclosed herein. One aspect of the present technology, for example, is directed toward an elongated shaft having an inner surface that defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of a distal portion. In some embodiments the distal portion includes an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure. The first portion can have a first stiffness and the second portion can have a second stiffness less than the first stiffness. The distal portion can further include an outer polymer structure disposed around the inner polymer structure and a coil wound around the inner polymer structure and disposed within the outer polymer structure.

This application is a continuation of U.S. patent application Ser. No.14/852,268, filed Sep. 11, 2015, the entire content of which isincorporated by reference herein.

TECHNICAL FIELD

The present technology relates generally to catheters. Morespecifically, the invention relates to catheter shaft construction.

BACKGROUND

A wide variety of medical devices have been developed for intravascularuse. Catheters, for example, are commonly used to facilitate navigationthrough and/or treatment within the anatomy of a patient. To direct thedistal portion of the catheter to the correct location in thevasculature, a physician must apply longitudinal forces, and sometimesrotational forces (i.e., torsional forces), from the proximal end of thecatheter. For the catheter shaft to transmit these forces from theproximal end to the distal end, the catheter must be sufficiently rigidto be pushed through the blood vessel (a property commonly referred toas “pushability”), yet flexible enough to navigate through the oftentortuous bends in the blood vessel. The catheter may also requiresufficient torsional stiffness to transmit the applied torque (aproperty commonly referred to as “torqueability”). A need exists forcatheter shafts that accomplish a balance between longitudinal rigidity,torsional stiffness, and flexibility.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on illustratingclearly the principles of the present disclosure.

FIG. 1A is a side view of a catheter in accordance with the presenttechnology.

FIG. 1B is a cross-sectional side view of a portion the catheter shaftshown in

FIG. 1A.

FIG. 2 is a cross-sectional side view of a portion of an elongatedcatheter shaft configured in accordance with another embodiment of thepresent technology.

FIG. 3 is a cross-sectional side view of a distal portion of anelongated catheter shaft configured in accordance with the presenttechnology.

FIG. 4 is a cross-sectional side view of a distal portion of anelongated catheter shaft configured in accordance with the presenttechnology.

FIG. 5 is a cross-sectional side view of a distal portion of anelongated catheter shaft configured in accordance with the presenttechnology.

FIG. 6 is a cross-sectional side view of a distal portion of anelongated shaft configured in accordance with the present technology.

FIG. 7 is a cross-sectional side view of a distal portion of anelongated shaft configured in accordance with the present technology.

FIG. 8 is a cross-sectional side view of a distal portion of anelongated shaft configured in accordance with the present technology.

DETAILED DESCRIPTION

The present technology is directed to catheters and associated methodsof manufacture. Specific details of several embodiments of catheterdevices, systems, and methods in accordance with the present technologyare described below with reference to FIGS. 1A-8 . With regard to theterms “distal” and “proximal” within this description, unless otherwisespecified, the terms can reference a relative position of the portionsof a catheter and/or an associated device with reference to an operatorand/or a location in the vasculature. Also, the term “thickness” as usedherein with respect to a particular material or layer refers to theperpendicular distance between the plane running through and generallyparallel with the radially outermost surface of the particular materialor layer and the plane running through and generally parallel with theradially innermost surface of the particular material or layer.

I. SELECTED EMBODIMENTS OF CATHETER SHAFTS OF THE PRESENT TECHNOLOGY

FIG. 1A is a side view of a catheter 100 configured in accordance withan embodiment of the present technology, and FIG. 1B is across-sectional side view of a portion of the catheter 100 shown in FIG.1A. Referring to FIGS. 1A-1B together, the catheter 100 includes ahandle assembly 101 and an elongated shaft 106 having a proximal portion106 a coupled to the handle assembly 101 and a distal portion 106 b. Thehandle assembly 101 includes a hub 102 configured to facilitateconnection to other devices (e.g., a syringe, a Y-adapter, etc.) and atransition portion 104 configured to provide strain relief at theproximal portion 106 a. In other embodiments, the handle assembly 101can have other suitable configurations based on the desired functionsand characteristics of the catheter 100.

The shaft 106 is a generally tubular member having an inner surface thatdefines a lumen 103 (FIG. 1B) extending from the proximal portion 106 aof the shaft 106 to an opening 118 at the distal terminus of the distalportion 106 b. In some embodiments, the shaft 106 can include aradiopaque marker 117 (FIG. 1B) surrounding the lumen 103 at or justproximal to the opening 118. The lumen 103 is configured to slidablyreceive and facilitate the passage therethrough of one or more medicaldevices, such as guidewires, balloon catheters, implants, intrasaccularocclusion devices (e.g., coils, expandable cages, expandable meshes,etc.), infusion devices, stents and/or stent-grafts, intravascularocclusion devices, clot retrievers, implantable heart valves, and othersuitable medical devices and/or associated delivery systems.Additionally, the lumen 103 is configured to receive one or more fluidstherethrough, such as radiopaque dye, saline, drugs, and the like.

The size of the lumen 103 can vary, depending on the desiredcharacteristics of the catheter 100. For example, in some embodimentsthe shaft 106 can have an inner diameter (e.g., lumen diameter) betweenabout 0.01 inches and about 0.05 inches (e.g., 0.017 inches, 0.0445inches, etc.), and in some embodiments between about 0.02 inches andabout 0.045 inches (e.g., 0.021 inches, etc.). In a particularembodiment, the inner diameter is between about 0.025 inches and about0.04 inches (e.g., 0.027 inches, 0.032 inches, etc.). Although the shaft106 shown in FIG. 1A has a generally round cross-sectional shape, itwill be appreciated that the shaft 106 can include other cross-sectionalshapes or combinations of shapes. For example, the cross-sectional shapeof the shaft 106 can be oval, rectangular, square, triangular,polygonal, and/or any other suitable shape and/or combination of shapes.

The outer diameter of the shaft 106 can be the same or vary along itslength. For example, in the embodiment shown in FIGS. 1A-1B, the shaft106 has a first portion 190 with a first diameter, a tapered portion 192with a diameter that decreases in a proximal to distal direction, and asecond portion 194 with a second diameter less than the first diameter.The length of the tapered portion 192 can be between about 1 cm andabout 5 cm. In some embodiments, the shaft 106 does not include a secondportion 194 and the tapered portion 192 extends distally to the distalterminus of the shaft 106. In other embodiments, the shaft 106 has anouter diameter that is generally constant along its length. Moreover,the length and/or outside diameter of the shaft 106 is generallyselected for the desired use of the catheter 100. For example, in thoseembodiments where the catheter 100 is configured as a guide catheter forenabling intravascular insertion and navigation, the outside diameter ofthe shaft 106 can be between about 3 Fr and about 10 Fr. In thoseembodiments where the catheter 100 is configured as a microcatheter foruse within small anatomies of the patient, the outside diameter of theshaft 106 can be between about 1 Fr and about 3 Fr.

Many embodiments of the present technology are particularly useful intreating targets located in tortuous and narrow vessels, such as certainsites in the neurovascular system, the coronary vascular system, or theperipheral vascular system (e.g., the superficial femoral, popliteal, orrenal arteries). Neurovascular target sites, such as sites in the brain,are often accessible only via a tortuous vascular path. Although someembodiments of the catheter 100 are described in terms of intravascularuse, in other embodiments the catheter 100 may be suited for uses in thedigestive system, soft tissues, and/or any other insertion into anorganism for medical uses. For example, in some embodiments, thecatheter 100 may be significantly shorter and used as an introducersheath, while in other embodiments the catheter 100 may be adapted forother medical procedures.

In the embodiment shown in FIG. 1B, the elongated shaft 106 includes aninner polymer structure 114 and an outer polymer structure 116surrounding at least a portion of the inner polymer structure 114. Theshaft 106 shown in FIG. 1B also has an inner braid 160 embedded in theouter polymer structure 116, an outer braid 162 surrounding at least aportion of the inner braid 160, and a coil 170 wrapped around at least aportion of the inner polymer structure 114. Each of these subcomponentswill now be described in greater detail.

Referring again to FIGS. 1A-1B together, the inner polymer structure 114extends from the proximal portion 106 a of the shaft 106 to a locationwithin the distal portion 106 b of the shaft 106. For example, in theembodiment shown in FIG. 1B, the inner polymer structure 114 extendsfrom the proximal portion 106 a of the shaft 106 to the opening 118 atthe distal terminus of the distal portion 106 b (e.g., the entire lengthof the shaft 106 or substantially the entire length of the shaft 106).In other embodiments, the inner polymer structure 114 extends along onlya portion of the length of the shaft 106 and/or has a proximal and/or adistal terminus that does not correspond to a proximal terminus and/or adistal terminus, respectively, of the shaft 106. The length of the innerpolymer structure 114 can vary depending upon, for example, the lengthof the shaft 106 and the desired characteristics and functions of thecatheter 100.

The inner polymer structure 114 can be made of any suitable polymer(and/or combination of multiples polymers) and by any suitable process.Suitable polymers can include, for example, polyoxymethylene (POM),polybutylene terephthalate (PBT), polyether block ester, polyether blockamide (PEBA), fluorinated ethylene propylene (FEP), polyethylene (PE),polypropylene (PP), polyvinylchloride (PVC), polyurethane,polytetrafluoroethylene (PTFE), polyether-ether ketone (PEEK),polyimide, polyamide, polyphenylene sulfide (PPS), polyphenylene oxide(PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA),polyether-ester, platinum, polymer/metal composites, etc., or mixtures,blends or combinations thereof, and may also include or be made up of alubricious polymer having a low coefficient of friction. In someembodiments (not shown), the inner polymer structure 114 includes one ormore metals or metal alloys and/or combinations thereof. In a particularembodiment, the inner polymer structure 114 does not include any polymermaterial and solely comprises a metal and/or metal alloy.

The inner polymer structure 114 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, in the embodiment shown in FIG. 1B, the inner polymerstructure 114 includes a first layer 112 and a second layer 113surrounding at least a portion of the first layer 112. An inner surfaceof the first layer 112 defines the shaft lumen 103. The first layer 112can comprise a lubricious polymer such as HDPE or PTFE, for example, orplatinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such asFEP, a copolymer of tetrafluoroethylene with perfluoroethers, such asperfluoroalkoxy alkanes (PFA) (more specifically, perfluoropropyl vinylether or perfluoromethyl vinyl ether), or the like. The second layer 113can be made of any of the materials described above with respect to theinner polymer structure 114 such as, for example, PEBA, PVC, PE, etc. Inother embodiments, the inner polymer structure 114 can be formed of asingle layer (e.g., only the first layer 112, only the second layer 113,etc.), and in other embodiments the inner polymer structure 114 caninclude more than two layers (e.g., three layers, four layers, etc.)depending upon the desired characteristics of the catheter 100. In someembodiments the first and second layers 112, 113 have generally the samelengths and are coextensive along the length of the shaft 106, and inother embodiments the first and second layers 112, 113 have differentlengths and/or are not coextensive along the shaft 106. For example, ina particular embodiment, the second layer 113 extends along only aportion of the length of the shaft 106 while the first layer 112 extendsthe entire length (or substantially the entire length) of the shaft 106.In any of the above embodiments, the first layer 112 can have athickness of about 0.0005 inches to about 0.005 inches, or about 0.001inches to about 0.003 inches. Also, in any of the above embodiments, thesecond layer 113 can have a thickness of about 0.0005 inches to about0.005 inches, or about 0.001 inches to about 0.003 inches.

The stiffness of the inner polymer structure 114 can be generallyuniform along its length, or the stiffness can vary along its length.The stiffness variation is a function of the size, shape, thickness,and/or materials of the inner polymer structure 114. In embodimentswhere the stiffness of the inner polymer structure 114 varies along itslength, the stiffness can change continuously (e.g., gradually) and/orbe stepped from one section to another. In some embodiments, thestiffness of the inner polymer structure 114 decreases in a proximal todistal direction along its length. In other embodiments, the stiffnessof the inner polymer structure 114 increases in a proximal to distaldirection along it length, and/or increases and decreases in a proximalto distal direction along its length. Additionally, the inner polymerstructure 114 can be made of or include a radiopaque material forradiographic visualization. Exemplary radiopaque materials include, forexample, gold, platinum, palladium, tantalum, tungsten alloy, polymermaterials loaded with radiopaque fillers, and the like. Likewise, insome embodiments, the inner polymer structure 114 is made of or includea material that may aid in MRI imaging, such as, for example, tungsten,Elgiloy, MP35N, nitinol, and others.

In the embodiment shown in FIGS. 1A-1B, the outer polymer structure 116directly contacts at least a portion of the inner polymer structure 114and encases at least a portion of each of the inner braid 160, the outerbraid 162, and the coil 170. The outer polymer structure 116 extendsdistally from the proximal portion 106 a of the shaft 106 to a locationwithin the distal portion 106 b of the shaft 106 (e.g., the entirelength of the shaft 106 or substantially the entire length of the shaft106). The length of the outer polymer structure 116 can vary dependingupon, for example, the length of the shaft 106 and the desiredcharacteristics and functions of the catheter 100. In some embodiments,the outer polymer structure 116 extends substantially the entire lengthof the shaft 106. In other embodiments, the outer polymer structure 116extends along only a portion of the length of the shaft 106 and/or has aproximal and/or distal terminus that does not correspond to a proximalterminus and/or distal terminus, respectively, of the shaft 106.

The outer polymer structure 116 (and/or portions thereof) can be made ofany suitable polymer (or composites or combinations thereof) and by anysuitable process. Suitable polymers can include, for example,polyoxymethylene (POM), polybutylene terephthalate (PBT), polyetherblock ester, polyether block amide (PEBA), fluorinated ethylenepropylene (FEP), polyethylene (PE), polypropylene (PP),polyvinylchloride (PVC), polyurethane, polytetrafluoroethylene (PTFE),polyether-ether ketone (PEEK), polyimide, polyamide, polyphenylenesulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon,perfluoro(propyl vinyl ether) (PFA), polyether-ester, platinum,polymer/metal composites, etc., or mixtures, blends or combinationsthereof. In several embodiments, the outer polymer structure 116 is orat least includes a lubricious polymer. In some embodiments (not shown),the outer polymer structure 116 includes one or more metals or metalalloys (combinations thereof). In a particular embodiment, the outerpolymer structure 116 does not include any polymer material and solelycomprises a metal and/or metal alloy.

In some embodiments, the stiffness of the outer polymer structure 116varies along its length. In such embodiments, the stiffness variationmay be continuous or stepped by varying the size, shape, thickness,and/or material composition of the outer polymer structure 116. Forexample, in the embodiment shown in FIGS. 1A-1B, the outer polymerstructure 116 includes four unique portions along its length (labeledproximal to distal as first, second, third and fourth portions 120, 130,140, and 150, respectively) in which the respective stiffnesses of theportions 120, 130, 140, 150 decrease sequentially in a proximal todistal direction. For example, the first portion 120 has a firststiffness, the second portion 130 has a second stiffness less than thefirst stiffness, the third portion 140 has a third stiffness less thanthe second stiffness, and the fourth portion 150 has a fourth stiffnessless than the third stiffness. In other embodiments, the stiffness ofthe outer polymer structure 116 and/or the stiffnesses of the individualportions 120, 130, 140, 150 can increase in a proximal to distaldirection (e.g., the second portion 130 can be stiffer than the firstportion 120, etc.), increase and decrease in a proximal to distaldirection (e.g., the second portion 130 can be stiffer than the firstportion 120 but less stiff than the third portion 140, etc.), or begenerally uniform in a proximal to distal direction. In otherembodiments, the outer polymer structure 116 can have more or fewerportions (e.g., one continuous portion, two portions, three portions,five portions, etc.).

In some embodiments, one or both of the first and second portions 120,130 can have an individual thickness of about 0.003 inches to about0.005 inches, and in some embodiments, about 0.004 inches to about 0.010inches. The fourth portion 150 can have a thickness of about 0.001inches to about 0.003 inches. The proximal portion of the taperedportion 192 can have a thickness equivalent to that of the correspondingsecond portion 130, and the distal portion of the tapered portion 192can have a thickness generally equivalent to that of the correspondingfourth portion 150. Thus, the third portion 140 can have a proximalthickness between about 0.003 inches to about 0.005 inches, or in someembodiments about 0.004 inches to about 0.010 inches, and a distalportion have a thickness of about 0.001 inches to about 0.003 inches.

The portions 120, 130, 140, 150, either individually or any combinationthereof, can be made of the same or different materials, have the sameor different size, have the same or different thickness, and/or have thesame or different cross-sectional shape. In some embodiments, the outerpolymer structure 116 can include two or more layers (e.g., an innerlayer surrounding an outer layer, etc.), and each layer can have thesame or different material compositions, thicknesses, and/orstiffnesses. Additionally, the portions 120, 130, 140, 150, eitherindividually or any combination thereof, can have a uniform or varyingstiffness along its respective length. In other words, the portions 120,130, 140, 150, either individually or any combination thereof, can havea uniform or varying size, shape, thickness, and/or material compositionalong its respective length. For example, in the embodiment shown inFIG. 1B, each of the portions 120, 130, 140, 150 has a constant materialcomposition and cross-sectional shape along its respective length. Eachof the first, second, and fourth portions 120, 130, 150 also has agenerally constant thickness along its respective length; accordingly,each of the first, second, and fourth portions 120, 130, 150 has agenerally constant stiffness along its respective length. The thirdportion 140, however, includes the tapered portion 192 (FIG. 1A) andthus varies in thickness (and stiffness) along its length. In otherembodiments, the third portion 140 does not coincide with the taperedportion 192 and/or the tapered portion 192 spans more than one of theportions 120, 130, 140, 150.

It will be appreciated that while the inner polymer structure 114 andthe outer polymer structure 116 are described herein as separatecomponents with respect to the illustrated embodiments, the inner andouter polymer structures 114, 116 can be provided as a single layer orstructure. For example, the inner polymer structure 114 and outerpolymer structure 116 may be provided separately, but attached orcombined together to physically form a single layer (e.g., a singlehomogeneous material).

Referring still to the embodiment shown in FIG. 1B, the inner braid 160is on and around the inner polymer structure 114, and the outer polymerstructure 116 is on and around the inner braid 160. In some embodiments,the inner braid 160 directly contacts at least a portion of both theinner polymer structure 114 and the outer polymer structure 116. Inother embodiments, the outer polymer structure 116 is between at least aportion of the inner polymer structure 114 and at least a portion of theinner braid 160. In the embodiment shown in FIGS. 1A-1B, the inner braid160 extends distally from the proximal portion 106 a of the shaft 106 toa distal terminus 160 b aligned with or just proximal of the distalterminus of the shaft 106. In other embodiments, the inner braid 160extends the entire length of the shaft 106. The length of the innerbraid 160 can vary depending upon, for example, the length of the shaft106 and the desired characteristics and functions of the catheter 100.

In some embodiments, at least a portion of the inner braid 160 iscoextensive with at least a portion of the outer braid 162. For example,in the embodiment shown in FIG. 1B, the inner braid 160 has a distalterminus 160 b located at a position along the shaft 106 distal of aproximal terminus (not shown) of the outer braid 162 and proximal of adistal terminus 162 b of the outer braid 162. In other embodiments (notshown), no portion of the inner braid 160 is coextensive with a portionof the outer braid 162. Additionally, in some embodiments at least aportion of the inner braid 160 is coextensive with at least a portion ofthe coil 170, and in other embodiments the inner braid 160 is adjacentto and/or spaced apart from the coil 170 along the length of the shaft106. For example, in the embodiment shown in FIG. 1B, the distalterminus 160 b of the inner braid 160 is located at a position along theshaft 106 proximal of a proximal terminus 170 a of the coil 170 suchthat no portion of the inner braid 160 is coextensive with any portionof the coil 170. Alternatively, in some embodiments (not shown) thedistal terminus 160 b of the inner braid 160 is located at a positionalong the shaft 106 distal of a proximal terminus 170 a of the coil 170such that at least a portion of the inner braid 160 is coextensive withat least a portion of the coil 170.

In the embodiment shown in FIGS. 1A-1B, the outer braid 162 is aroundthe inner braid 160, and the outer polymer structure 116 contacts theouter braid 162. In some embodiments the outer braid 162 directlycontacts the inner braid 160. In other embodiments, the outer polymerstructure 116 is between at least a portion of the inner braid 160 andat least a portion of the outer braid 162. In the embodiment shown inFIG. 1B, a distal portion of the outer braid 162 is around a proximalportion of the coil 170. In some embodiments the outer braid 162directly contacts the coil 170. In other embodiments, the outer polymerstructure 116 is between at least a portion of the outer braid 162 andat least a portion of the coil 170.

The outer braid 162 extends distally from the proximal portion 106 a ofthe shaft 106 to a distal terminus 162 b proximal to the distal terminusof the shaft 106. In other embodiments, the outer braid 162 extends theentire length of the shaft 106. The length of the outer braid 162 canvary depending upon, for example, the length of the shaft 106 and thedesired characteristics and functions of the catheter 100. In someembodiments, at least a portion of the outer braid 162 is coextensivewith at least a portion of the coil 170. For example, in the embodimentshown in FIG. 1B, the distal terminus 162 b of the outer braid 162 islocated at a position along the shaft 106 that is distal of the proximalterminus 170 a of the coil 170. In those embodiments where at least aportion of the outer braid 162 is coextensive with at least a portion ofthe coil 170, the coextensive portions of the outer braid 162 and thecoil 170 form an overlapping region 180. As shown in FIG. 1B, in someembodiments the outer braid 162 surrounds the coil 170 within theoverlapping region 180. In other embodiments, the coil 170 surrounds theouter braid 162 within the overlapping region 180 (FIG. 2 , described ingreater detail below). In yet other embodiments, the outer braid 162 isspaced apart from and/or adjacent to the coil 170 such that no portionof the outer braid 162 is coextensive with any portion of the coil 170.

The inner braid 160 and/or the outer braid 162 can individually have agenerally uniform pitch along its respective length or may have avarying pitch along its respective length. The flexibility of theindividual inner braid 160 and/or the outer braid 162 may varycontinuously along its respective length by continuously varying thepitch or may vary along its respective length in a stepwise fashion bystepwise varying the pitch. Moreover, the inner braid 160 and/or theouter braid 162 can individually have a generally constant braid anglealong its respective length or have a varying braid angle along itsrespective length to provide different zones of stiffness and/orflexibility. The inner braid 160 and/or the outer braid 162 can beformed of braided filaments having the same or varying diameters(individually and/or relative to the other braid). In some embodiments,the inner braid 160 and/or the outer braid 162 are further shaped usinga heat setting process. Additionally, the inner braid 160 and the outerbraid 162 can have the same or different pitch, stiffness, braid angle,filament diameters, and filament count. In some embodiments, the innerand/or outer braids 160, 162 individually have a pitch of 45 PPI to 80PPI. In a particular embodiment, the shaft 106 includes a single braid.Additionally, in some embodiments, the inner braid 160 and/or the outerbraid 162 can be made of or include a radiopaque or imaging material.

The inner 160 and/or outer braids 162 are formed of a plurality ofinterwoven wires. The wires can have a circular or rectangularcross-sectional shape. The wires can be made of one or more metals, suchas stainless steel, platinum, silver, tantalum, and the like. In someembodiments, the wires can include or be made of non-metallic materials.In some embodiments, the wires are made of a superelastic orshape-memory material, such as nitinol. For those embodiments utilizingwires having a rectangular shape, the wires can have a cross-sectionalarea of about 0.0005 inches by 0.0025 inches to about 0.001 inches by0.005 inches.

The coil 170 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 114. In the embodiment shown inFIGS. 1A-1B, the outer polymer structure 116 encases the coil 170. Theproximal terminus 170 a of the coil 170 is positioned along the distalportion 106 b of the shaft 106, and the distal terminus 170 b of thecoil 170 is positioned generally in alignment with or just proximal tothe distal terminus of the shaft 106. Accordingly, the coil 170 iscompletely disposed within the distal portion of the shaft. In otherembodiments, at least a portion of the coil 170 is outside of the distalportion 106 b of the shaft 106. The pitch of adjacent turns of the coil170 may be tightly wound so that each turn touches the succeeding turnor the pitch may be set such that the coil 170 is wound in an openfashion. The pitch of the coil 170 can be the same or may vary along thelength of the coil 170. The coil 170 can have a pitch of about 0.004inches to about 0.014 inches. In some embodiments, the pitch of the coil170 depends on the inner diameter of the shaft 106. For example, for ashaft inner diameter of about 0.017 inches, the coil 170 can have apitch of about 0.004 inches to about 0.009 inches. For a shaft innerdiameter of about 0.021 inches, the coil 170 can have a pitch of about0.006 inches to about 0.011 inches. For a shaft inner diameter of about0.027 inches, the coil 170 can have a pitch of about 0.007 inches toabout 0.012 inches. For a shaft inner diameter of about 0.0045 inches,the coil 170 can have a pitch of about 0.010 inches to about 0.014inches. Additionally, in some embodiments, the coil 170 or portionsthereof can be made of or include a radiopaque or imaging material.

The wire of the coil 170 can be made of one or more metals, such asstainless steel, platinum, silver, tantalum, and the like. In otherembodiments, the wire of the coil 170 can include or be made ofnon-metallic materials. In a particular embodiment, the wires are madeof a superelastic or shape-memory material, such as nitinol The wire canhave an outer diameter of about 0.001 inches to about 0.005 inches, orin some embodiments about 0.001 inches to about 0.003 inches.

It will be appreciated that the inner braid 160, outer braid 162, andcoil 170 can have other suitable configurations and/or relativepositions along the length of the shaft 106. For example, in someembodiments the inner braid 160 can be coextensive with at least aportion of the coil 170, and in some embodiments the inner braid 160 canbe generally coextensive with the outer braid 162. In a particularembodiment, at least a portion of the outer braid 162 is not coextensivewith a portion of the coil 170.

FIG. 2 is a cross-sectional side view of a portion of a catheter shaft206 configured in accordance with another embodiment of the presenttechnology. The shaft 206 can be generally similar to the shaft 106shown in FIGS. 1A-1B, except the coil 170 in the shaft 206 of FIG. 2surrounds the outer braid 162 within the overlapping region 180.

II. SELECTED EMBODIMENTS OF DISTAL PORTIONS OF CATHETER SHAFTS OF THEPRESENT TECHNOLOGY

FIGS. 3-8 are cross-sectional side views of distal portions of cathetershafts configured in accordance with the present technology. Any of thedistal portions (or aspects thereof) described below can be combinedwith any of the catheter shafts described above with reference to FIGS.1A-2 . As described in greater detail below, the distal portionembodiments of the present technology include regions of varyingstiffness and/or preferential bending that provide improvedbending/buckling at the distal portion when contacting the wall oftortuous vessels, thereby improving ease of navigation of thecorresponding shaft and/or distal portion.

FIG. 3 is a cross-sectional side view of a distal portion 300 of acatheter shaft configured in accordance with the present technology. Thedistal portion 300 can include a radiopaque marker 317, an inner polymerstructure 314, an outer polymer structure 316 surrounding at least aportion of the inner polymer structure 314, and a coil 370 wrappedaround at least a portion of the inner polymer structure 314. As shownin FIG. 3 , the inner polymer structure 314 extends the length of thedistal portion 300 such that the inner polymer structure 314 terminatesdistally at an opening 318 at the distal terminus of the distal portion300. The inner polymer structure 314 defines a lumen that can begenerally continuous with the lumen 103 of any of the shaft embodimentsdescribed above with reference to FIGS. 1A-2 .

The inner polymer structure 314 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, in the embodiment shown in FIG. 3 , the inner polymerstructure 314 includes a first layer 312 and a second layer 313surrounding the first layer 312. Accordingly, an inner surface of thefirst layer 312 defines the shaft lumen 103 at the distal portion 300.The first layer 312 can comprise a lubricious polymer such as HDPE orPTFE, for example, or platinum, PEEK, PE, PP, or a copolymer oftetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylenewith perfluoroethers, such as PFA (more specifically, perfluoropropylvinyl ether or perfluoromethyl vinyl ether), or the like. The secondlayer 313 can be made of any of the materials described above withrespect to the inner polymer structure 114. Moreover, in someembodiments the inner polymer structure 314 can be formed of a singlelayer (e.g., only the first layer 312, only the second layer 313, etc.),and in other embodiments the inner polymer structure 314 can includemore than two layers (e.g., three layers, four layers) depending on thedesired characteristics of the distal portion 300 of the catheter.

The stiffness of the inner polymer structure 314 can be generallyuniform along its length, or the stiffness can vary along its length. Inthe embodiment shown in FIG. 3 , the second layer 313 of the innerpolymer structure 314 includes two unique portions along its length(labeled proximal to distal as first portion 319 and second portion320). The first and second portions 319, 320 can have at least one of adifferent size, shape, thickness, and material composition such that thefirst portion 319 has a different stiffness than the second portion 320(or in other words, the second portion 320 is softer than the firstportion 319). For example, the first portion 319 can be a first materialand the second portion 320 can be a second material different than thefirst material such that a stiffness of the first portion 319 is greaterthan a stiffness of the second portion 320. In other embodiments, astiffness of the inner polymer structure 314 can increase in a proximalto distal direction along its length, or increase and decrease in aproximal to distal direction along its length. For example, in aparticular embodiment, the second portion 320 can have a stiffness thatis greater than or equal to the stiffness of the first portion 319. Inother embodiments, the inner polymer structure 314 can have more orfewer portions (e.g., one continuous portion, three portions, fourportions, etc.).

In the embodiment shown in FIG. 3 , both the first and second layers312, 313 of the inner polymer structure 314 extend along the entirelength of the distal portion 300 such that the distal termini of boththe first and second layers 312, 313 are at the distal terminus of thedistal portion 300. Additionally, the second portion 319 of the secondlayer 313 defines a portion of the distal terminus of the distal portion300 of the shaft. As such, the distal-most surfaces of both the innerand the outer polymer structures 314, 316 define the distal terminus ofthe distal portion 300 of the shaft. In other embodiments, the firstlayer 312 terminates proximal to the distal terminus of the distalportion 300.

Although the inner polymer structure 314 is shown having two portions319, 320 in FIG. 3 , in other embodiments the inner polymer structure314 can have a single continuous portion or more than two portions(e.g., three portions, four portions, etc.). Moreover, although thesecond layer 313 is shown having multiple portions, in other embodimentsthe first layer 312 can additionally or alternatively include multipleportions.

Referring still to the embodiment shown in FIG. 3 , the outer polymerstructure 316 directly contacts at least a portion of the inner polymerstructure 314 and encases at least a portion of the coil 370. Forexample, in the embodiment shown in FIG. 3 , at least a portion of thesurface of the coil 370 directly contacts the first and second portions319, 320 of the second layer 313 of the inner polymer structure 314,while a remaining portion of the coil's surface directly contacts theouter polymer structure 316. Additionally, the outer polymer structure316 extends along the length of the distal portion 300 such that adistal terminus of the outer polymer structure 316 corresponds to thedistal terminus of the distal portion 300. In other embodiments, theouter polymer structure 316 extends along only a portion of the lengthof the distal portion 300 and/or has a proximal and/or distal terminusthat does not correspond to a proximal terminus and/or distal terminus,respectively, of the distal portion 300. Moreover, the outer polymerstructure 316 (and/or portions thereof) can be made of any of thematerials described above with respect to the outer polymer structure116.

The coil 370 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 314, and the outer polymerstructure 316 can encase at least a portion of the coil 370. The coil370 can extend all or a portion of the length of the distal portion 300.For example, in the embodiment shown in FIG. 3 , the coil 370 has adistal terminus that is aligned with or just proximal of the radiopaquemarker 317, and the radiopaque marker 317 is proximal of the distalterminus of the distal portion 300. As such, a distal terminus of thecoil 370 is spaced apart from a distal terminus of the shaft. The pitchof adjacent turns of the coil 370 may be tightly wound so that each turntouches the succeeding turn or the pitch may be set such that the coil370 is wound in an open fashion. The pitch of the coil 370 can be thesame or vary along the length of the coil 370. Additionally, in someembodiments, the coil 370 or portions thereof can be made of or includea radiopaque or imaging material.

FIG. 4 is a cross-sectional side view of a distal portion 400 of acatheter shaft configured in accordance with another embodiment of thepresent technology. The distal portion 400 can include a radiopaquemarker 417, an inner polymer structure 414, an outer polymer structure416 surrounding at least a portion of the inner polymer structure 414,and a coil 470 wound around at least a portion of the inner polymerstructure 414. The inner polymer structure 414 defines a lumen that canbe generally continuous with the lumen 103 of any of the shaftembodiments described above with reference to FIGS. 1A-2 .

The inner polymer structure 414 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, in the embodiment in FIG. 4 , the inner polymer structure414 includes a first layer 412 and a second layer 413 surrounding thefirst layer 412. Accordingly, an inner surface of the first layer 412defines the shaft lumen 103 at the distal portion 400. The first layer412 can comprise a lubricious polymer such as HDPE or PTFE, for example,or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, suchas FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such asPFA (more specifically, perfluoropropyl vinyl ether or perfluoromethylvinyl ether), or the like. The second layer 413 can be made of any ofthe materials described above with respect to the inner polymerstructure 414. Moreover, in some embodiments the inner polymer structure414 can be formed of a single layer (e.g., only the first layer 412,only the second layer 413, etc.), and in other embodiments the innerpolymer structure 414 can include more than two layers (e.g., threelayers, four layers) depending upon the desired characteristics of thecatheter.

The stiffness of the inner polymer structure 414 can be generallyuniform along its length, or the stiffness can vary along its length. Inthe embodiment shown in FIG. 4 , the second layer 413 of the innerpolymer structure 414 includes two unique portions (labeled proximal todistal as first portion 419 and second portion 420) adjacent one anotheralong its length having different stiffnesses. The first and secondportions 419, 420 can have at least one of a different size, shape,thickness, and material composition such that the first portion 419 hasa different stiffness than the second portion 420. For example, thefirst portion 419 can be a first material and the second portion 420 canbe a second material different than the first material such that astiffness of the first portion 419 is greater than a stiffness of thesecond portion 420. In other embodiments, a stiffness of the innerpolymer structure 414 can increase in a proximal to distal directionalong its length, or increase and decrease in a proximal to distaldirection along its length. For example, in a particular embodiment, thesecond portion 420 has a stiffness that is greater than or equal to thestiffness of the first portion 419.

In the embodiment shown in FIG. 4 , the second layer 413 of the innerpolymer structure 414 extends along only a portion of the length of thedistal portion 400 such that a distal terminus of the second layer 413is proximal of the distal terminus of the outer polymer structure 416and the distal terminus of the distal portion 400. Accordingly, incontrast to the embodiment shown in FIG. 3 , only the distal-mostportions of the outer polymer structure 416 and the first layer 312define the distal terminus of the distal portion 400 of the shaft (andnot the second layer 313). Likewise, a distal region 421 of the distalportion 400 does not include the second layer 413 and comprises only thefirst layer 412, the outer polymer structure 416, the radiopaque marker417, and a portion of the coil 470. Accordingly, the distal region 421is more flexible than the remainder of the distal portion 400. In someembodiments, the first layer 412 and/or the coil 470 terminates proximalof the distal region 421 such that the distal region 412 comprises thefirst layer 412 and the outer polymer structure 416. The length of thedistal region 421 can be between about 0.5 mm and about 5 cm.

Although the inner polymer structure 414 is shown having two portions419, 420 in FIG. 4 , in other embodiments the inner polymer structure414 can have a single continuous portion or more than two portions(e.g., three portions, four portions, etc.). Moreover, although thesecond layer 413 is shown having multiple portions, in other embodimentsthe first layer 412 can additionally or alternatively include multipleportions.

Referring still to the embodiment shown in FIG. 4 , the outer polymerstructure 416 directly contacts at least a portion of the inner polymerstructure 414 and encases at least a portion of the coil 470. Forexample, in the embodiment shown in FIG. 4 , at least a portion of thesurface of the coil 470 directly contacts the inner polymer structure414, while a remaining portion of the coil's surface directly contactsthe outer polymer structure 416. As shown in FIG. 4 , in someembodiments the outer polymer structure 416 extends along the length ofthe distal portion 400 such that a distal terminus of the outer polymerstructure 416 corresponds to the distal terminus of the distal portion400. The outer polymer structure 416 (and/or portions thereof) can bemade of any of the materials described above with respect to the outerpolymer structure 116.

The coil 470 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 414. The coil 470 can extendall or a portion of the length of the distal portion 400. For example,in the embodiment shown in FIG. 4 , the coil 470 has a distal terminusthat is aligned with or just proximal of the radiopaque marker 417, andthe radiopaque marker 417 is proximal of the distal terminus of thedistal portion 400. The pitch of adjacent turns of the coil 470 may betightly wound so that each turn touches the succeeding turn or the pitchmay be set such that the coil 470 is wound in an open fashion. The pitchof the coil 470 can be the same or vary along the length of the coil470. Additionally, in some embodiments, the coil 470 or portions thereofcan be made of or include a radiopaque or imaging material.

The distal portions 300/400 provide several advantages over distalportions of conventional catheters, especially microcatheters fordelivering occlusive devices (such as coils) to cerebral aneurysms. Forexample, the distal portions 300 and 400 have a (relatively) softerdistal tip and a (relatively) stiffer region immediately adjacent andproximal to the softer distal tip. Such a construction allows forimproved bending and trackability at the distal tip bend (forpositioning at the aneurysm neck) while the proximal stiffer region ofthe distal portion 300/400 provides additional support and stability tothe distal portion 300/400, thereby lessening or preventing kickback ofthe shaft during deployment of an occlusive device (such as a coil) inan aneurysm.

FIG. 5 is a cross-sectional side view of a distal portion 500 of acatheter shaft configured in accordance with another embodiments of thepresent technology. The distal portion 500 can include a radiopaquemarker 517, an inner polymer structure 514, an outer polymer structure516 surrounding at least a portion of the inner polymer structure 514,and a coil 570 wound around at least a portion of the inner polymerstructure 514. In the embodiment shown in FIG. 5 , the inner polymerstructure 514 extends the length of the distal portion 500 such that theinner polymer structure 514 terminates distally at an opening 518 at thedistal terminus of the distal portion 500. The inner polymer structure514 defines a lumen that can be generally continuous with the lumen 103of any of the shaft embodiments described above with reference to FIGS.1A-2 .

The inner polymer structure 514 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, in the embodiment shown in FIG. 5 , the inner polymerstructure 514 includes a first layer 512 and a second layer 513surrounding the first layer 512. As such, an inner surface of the firstlayer 512 defines the shaft lumen 103. The second layer 513 can be madeof any of the materials described above with respect to the innerpolymer structure 514. The first layer 512 can comprise a lubriciouspolymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, ora copolymer of tetrafluoroethylene, such as FEP, a copolymer oftetrafluoroethylene with perfluoroethers, such as PFA (morespecifically, perfluoropropyl vinyl ether or perfluoromethyl vinylether), or the like. Moreover, in some embodiments the inner polymerstructure 514 can be formed of a single layer (e.g., only the firstlayer 512, only the second layer 513, etc.), and in other embodimentsthe inner polymer structure 514 can include more than two layers (e.g.,three layers, four layers) depending upon the desired characteristics ofthe device.

The outer polymer structure 516 directly contacts at least a portion ofthe inner polymer structure 514 and encases at least a portion of thecoil 570. For example, in the embodiment shown in FIG. 5 , at least aportion of the surface of the coil 570 directly contacts the secondlayer 513 of the inner polymer structure 514, while a remaining portionof the coil's surface directly contacts the outer polymer structure 516.As shown in FIG. 5 , in some embodiments the outer polymer structure 516extends along the length of the distal portion 500 such that a distalterminus of the outer polymer structure 516 corresponds to the distalterminus of the distal portion 500. The outer polymer structure 516(and/or portions thereof) can be made of any of the materials describedabove with respect to the outer polymer structure 116.

The coil 570 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 514. The coil 570 can extendall or a portion of the length of the distal portion 500. For example,in the embodiment shown in FIG. 5 , the coil 570 has a distal terminusthat is aligned with or just proximal of the radiopaque marker 517, andthe radiopaque marker 517 is proximal of the distal terminus of thedistal portion 500. The pitch of adjacent turns of the coil 570 may betightly wound so that each turn touches the succeeding turn or the pitchmay be set such that the coil 570 is wound in an open fashion. The pitchof the coil 570 can be the same or vary along the length of the coil570. For example, in the embodiment shown in FIG. 5 , the coil 570 has afirst portion 572 and a second portion 574 distal of the first portion572. The first portion 572 has a first pitch and the second portion 574has a second pitch that is greater than the first pitch. Accordingly, alength of the distal portion 500 corresponding to the first portion 572of the coil 570 is less flexible than a length of the distal portion 500corresponding to the second portion 574 of the coil 570. Additionally,in some embodiments, the coil 570 or portions thereof can be made of orinclude a radiopaque or imaging material.

FIG. 6 is a cross-sectional side view of a distal portion 600 of acatheter shaft configured in accordance with the present technology. Thedistal portion 600 can include a radiopaque marker 617, an inner polymerstructure 614, an outer polymer structure 616 surrounding at least aportion of the inner polymer structure 614, and a coil 670 wound aroundat least a portion of the inner polymer structure 614. In the embodimentshown in FIG. 6 , the inner polymer structure 614 extends the length ofthe distal portion 600 such that the inner polymer structure 614terminates distally at an opening 618 at the distal terminus of thedistal portion 600. The inner polymer structure 614 defines a lumen thatcan be generally continuous with the lumen 103 of any of the shaftembodiments described above with reference to FIGS. 1A-2 .

The inner polymer structure 614 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, as shown in FIG. 6 , the inner polymer structure 614 caninclude a first layer 612 and a second layer 613 surrounding the firstlayer 612. As such, an inner surface of the first layer 612 defines theshaft lumen 103. The second layer 613 can be made of any of thematerials described above with respect to the inner polymer structure614. The first layer 612 can include a lubricious polymer such as HDPEor PTFE, for example, or a copolymer of tetrafluoroethylene withperfluoroalkyl vinyl ether (PFA) (more specifically, perfluoropropylvinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, insome embodiments the inner polymer structure 614 can be formed of asingle layer (e.g., only the first layer 612, only the second layer 613,etc.), and in other embodiments the inner polymer structure 614 caninclude more than two layers (e.g., three layers, four layers) dependingupon the desired characteristics of the device.

The outer polymer structure 616 directly contacts at least a portion ofthe inner polymer structure 614 and encases at least a portion of thecoil 670. For example, in the embodiment shown in FIG. 6 , at least aportion of the surface of the coil 670 directly contacts the secondlayer 613 of the inner polymer structure 614, while a remaining portionof the coil's surface directly contacts the outer polymer structure 616.In some embodiments the outer polymer structure 616 extends along thelength of the distal portion 600 such that a distal terminus of theouter polymer structure 616 corresponds to the distal terminus of thedistal portion 600. The outer polymer structure 616 (and/or portionsthereof) can be made of any of the materials described above withrespect to the outer polymer structure 116.

The coil 670 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 614. The coil 670 can extendall or a portion of the length of the distal portion 600. For example,in the embodiment shown in FIG. 6 , the coil 670 has a distal terminusthat is aligned with or just proximal of the radiopaque marker 617, andthe radiopaque marker 617 is proximal of the distal terminus of thedistal portion 600. The pitch of adjacent turns of the coil 670 may betightly wound so that each turn touches the succeeding turn or the pitchmay be set such that the coil 670 is wound in an open fashion. The pitchof the coil 670 can be the same or vary along the length of the coil670. For example, in the embodiment shown in FIG. 6 , the coil 670 has afirst portion 672, a second portion 674 distal of the first portion 672,and a third portion 676 distal of the second portion 674. The firstportion 672 has a first pitch, the second portion 674 has a second pitchless than the first pitch, and the third portion 676 has a third pitchgreater than the second pitch. Accordingly, regions of the distalportion 600 corresponding to the first and third portions 672, 676 ofthe coil 670 are more flexible than a region of the distal portion 600corresponding to the second portion 674 of the coil 670. In someembodiments, the first and third pitches can be the same or different solong as the average pitch of the first and third portions 672, 676 isless than the average pitch of the second portion 674. Additionally, insome embodiments, the coil 670 or portions thereof can be made of orinclude a radiopaque or imaging material.

FIG. 7 is a cross-sectional side view of a distal portion 700 of acatheter shaft configured in accordance with the present technology. Thedistal portion 700 can include a radiopaque marker 717, an inner polymerstructure 714, an outer polymer structure 716 surrounding at least aportion of the inner polymer structure 714, and a coil 770 wound aroundat least a portion of the inner polymer structure 714. In the embodimentshown in FIG. 7 , the inner polymer structure 714 extends the length ofthe distal portion 700 such that the inner polymer structure 714terminates distally at an opening 718 at the distal terminus of thedistal portion 700. The inner polymer structure 714 defines a lumen thatcan be generally continuous with the lumen 103 of any of the shaftembodiments described above with reference to FIGS. 1A-2 .

The inner polymer structure 714 can include a single layer of materialor it can have two or more layers of the same or different materials.For example, as shown in FIG. 7 , the inner polymer structure 714 caninclude a first layer 712 and a second layer 713 surrounding the firstlayer 712. As such, an inner surface of the first layer 712 defines theshaft lumen 103. The second layer 713 can be made of any of thematerials described above with respect to the inner polymer structure714. The first layer 712 can comprise a lubricious polymer such as HDPEor PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer oftetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylenewith perfluoroethers, such as PFA (more specifically, perfluoropropylvinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, insome embodiments the inner polymer structure 714 can be formed of asingle layer (e.g., only the first layer 712, only the second layer 713,etc.), and in other embodiments the inner polymer structure 714 caninclude more than two layers (e.g., three layers, four layers) dependingupon the desired characteristics of the device.

The outer polymer structure 716 directly contacts at least a portion ofthe inner polymer structure 714 and encases at least a portion of thecoil 770. For example, in the embodiment shown in FIG. 7 , at least aportion of the surface of the coil 770 directly contacts the secondlayer 713 of the inner polymer structure 714, while a remaining portionof the coil's surface directly contacts the outer polymer structure 716.In some embodiments the outer polymer structure 716 extends along thelength of the distal portion 700 such that a distal terminus of theouter polymer structure 716 corresponds to the distal terminus of thedistal portion 700. The outer polymer structure 716 (and/or portionsthereof) can be made of any of the materials described above withrespect to the outer polymer structure 116.

The coil 770 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 714. The coil 770 can extendall or a portion of the length of the distal portion 700. For example,in the embodiment shown in FIG. 7 , the coil 770 has a distal terminusthat is aligned with or just proximal of the radiopaque marker 717, andthe radiopaque marker 717 is proximal of the distal terminus of thedistal portion 700. The pitch of adjacent turns of the coil 770 may betightly wound so that each turn touches the succeeding turn or the pitchmay be set such that the coil 770 is wound in an open fashion. The pitchof the coil 770 can be the same or vary along the length of the coil770. For example, in the embodiment shown in FIG. 7 , the coil 770 has afirst portion 772, a second portion 774 distal of the first portion 772,a third portion 776 distal of the second portion 774, and a fourthportion 778 distal of the third portion 776. The first portion 772 has afirst pitch, the second portion 774 has a second pitch greater than thefirst pitch, the third portion 776 has a third pitch less than thesecond pitch, and the fourth portion 778 has a fourth pitch greater thaneach of the first and third pitches. Accordingly, regions of the distalportion 700 corresponding to the first and third portions 772, 776 ofthe coil 770 are less flexible than regions of the distal portion 700corresponding to the second and fourth portions 774, 778 of the coil770.

In some embodiments, the first and third pitches can be generally thesame, and the second and fourth pitches can be generally the same andgreater than the first and third pitches. In other embodiments, thefirst and third portions 772, 776 can have the same and/or differentpitches and/or the second and fourth portions 774, 778 can have the sameand/or different pitches, so long as the average pitch of the first andthird portions 772, 776 is less than the average pitch of the second andfourth portions 774, 778. Additionally, in some embodiments, the coil770 or portions thereof can be made of or include a radiopaque orimaging material.

FIG. 8 is a cross-sectional side view of a distal portion 800 of acatheter shaft configured in accordance with the present technology. Thedistal portion 800 can include a radiopaque marker 817, an inner polymerstructure 814, an outer polymer structure 816 surrounding at least aportion of the inner polymer structure 814, and a coil 870 wound aroundat least a portion of the inner polymer structure 814. In the embodimentshown in FIG. 8 , the inner polymer structure 814 extends the length ofthe distal portion 800 such that the inner polymer structure 814terminates distally at an opening 818 at the distal terminus of thedistal portion 800. The inner polymer structure 814 defines a lumen thatcan be generally continuous with the lumen 103 of any of the shaftembodiments described above with reference to FIGS. 1A-2 .

The inner polymer structure 814 can include two or more layers. Forexample, as shown in FIG. 8 , the inner polymer structure 814 caninclude a first layer 812 and a second layer 813 surrounding the firstlayer 812. As such, an inner surface of the first layer 812 defines theshaft lumen 103. The second layer 813 can be made of any of thematerials described above with respect to the inner polymer structure814. The first layer 812 can comprise a lubricious polymer such as HDPEor PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer oftetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylenewith perfluoroethers, such as PFA (more specifically, perfluoropropylvinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, insome embodiments the inner polymer structure 814 can be formed of asingle layer (e.g., only the first layer 812, only the second layer 813,etc.), and in other embodiments the inner polymer structure 814 caninclude more than two layers (e.g., three layers, four layers) dependingupon the desired characteristics of the device.

The outer polymer structure 816 directly contacts at least a portion ofthe inner polymer structure 814 and encases at least a portion of thecoil 870. For example, in the embodiment shown in FIG. 8 , at least aportion of the surface of the coil 870 directly contacts the secondlayer 813 of the inner polymer structure 814, while a remaining portionof the coil's surface directly contacts the outer polymer structure 816.In some embodiments the outer polymer structure 816 extends along thelength of the distal portion 800 such that a distal terminus of theouter polymer structure 816 corresponds to the distal terminus of thedistal portion 800. The outer polymer structure 816 (and/or portionsthereof) can be made of any of the materials described above withrespect to the outer polymer structure 116.

The coil 870 can be one or more round wires or flat ribbons helicallywound around the inner polymer structure 814. The coil 870 can extendall or a portion of the length of the distal portion 800. For example,in the embodiment shown in FIG. 8 , the coil 870 has a distal terminusthat is aligned with or just proximal of the radiopaque marker 817, andthe radiopaque marker 817 is proximal of the distal terminus of thedistal portion 800. The pitch of adjacent turns of the coil 870 may betightly wound so that each turn touches the succeeding turn or the pitchmay be set such that the coil 870 is wound in an open fashion. The pitchof the coil 870 can be the same or vary along the length of the coil870. For example, in the embodiment shown in FIG. 8 , the coil 870 has afirst portion 872, a second portion 874 distal of the first portion 872,and a third portion 876 distal of the second portion 874. The firstportion 872 has a first pitch, the second portion 874 has a second pitchgreater than the first pitch, and the third portion 876 has a thirdpitch less than the second pitch. Accordingly, regions of the distalportion 800 corresponding to the first and third portions 872, 876 ofthe coil 870 are less flexible than a region of the distal portion 800corresponding to the second portion 874 of the coil 870. In someembodiments, the first and third pitches can be the same or different solong as the average pitch of the first and third portions 872, 876 isless than the average pitch of the second portion 874. Additionally, insome embodiments, the coil 870 or portions thereof can be made of orinclude a radiopaque or imaging material.

In the embodiment shown in FIG. 8 , the coil 870 has a first portion 872having a first pitch, a second portion 874 having a second pitch greaterthan the first pitch, and a third portion 876 have a third pitch lessthan the second pitch. The first and third pitches can be the same ordifferent. The third portion 876 can be distal of the second portion874, and the second portion 874 can be distal of the first portion 872.

III. SELECTED METHODS OF MANUFACTURE

The outer polymer structure 116 can be constructed and disposed usingany appropriate technique, for example, by extrusion, co-extrusion, ILC,coating, heat shrink techniques, heat bonding, casting, molding, fusingone or several segments of an outer polymer structure materialend-to-end, or the like. The outer polymer structure 116 can be securedto the inner polymer structure 114, the coil 170, the inner braid 160,and/or the outer braid 162 by any of the above techniques. Inembodiments where the outer polymer structure 116 is constructedindependently of the other portions of the shaft 106, the outer polymerstructure 116 may be thereafter secured to the inner polymer structure114, the inner braid 160, the outer braid 162, and/or the coil 170 usingsuitable techniques such as adhesive bonding, crimping, frictionfitting, mechanically fitting, chemically bonding, thermally bonding,welding (e.g., resistance, RF, or laser welding), soldering, brazing, orthe use of a connector member or material, or the like, or combinationsthereof.

IV. CONCLUSION

Several other embodiments of the technology can have different states,components, or procedures than those described herein. Moreover, it willbe appreciated that specific elements, substructures, advantages, uses,and/or other features of the embodiments described with reference toFIGS. 1A-8 can be suitably interchanged, substituted or otherwiseconfigured with one another in accordance with additional embodiments ofthe present technology. For example, any of the distal portionsdescribed with reference to FIGS. 3-8 can be combined with any of theelongated shafts and/or catheter systems described with references toFIGS. 1A-2 . Furthermore, suitable elements of the embodiments describedwith reference to FIGS. 1A-8 can be used as standalone and/orself-contained devices. A person of ordinary skill in the art,therefore, will accordingly understand that the technology can haveother embodiments with additional elements, or the technology can haveother embodiments without several of the features shown and describedabove with reference to FIGS. 1A-8 .

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theexampled invention. Accordingly, it is to be understood that thedrawings and descriptions herein are proffered by way of example tofacilitate comprehension of the invention and should not be construed tolimit the scope thereof.

We claim:
 1. A catheter comprising: an elongated shaft having a proximalportion, a distal portion, and an intermediate portion therebetween,wherein the distal portion terminates distally at an opening; wherein:the intermediate portion has a proximal region, an overlapping region,and a distal region, the overlapping region being between the proximaland distal regions; the proximal region extends from the proximalportion of the shaft to the overlapping region; the proximal regionincludes an inner polymer structure, an outer polymer structure, aninner braid, and an outer braid surrounding the inner braid; the outerpolymer structure is disposed in and around the inner braid and theouter braid; the inner braid comprises a first plurality of interwovenwires; the outer braid comprises a second plurality of interwoven wires;the overlapping region extends from the proximal region to the distalregion; the overlapping region includes: (a) the inner polymerstructure, (b) the outer polymer structure, (c) a coil wound around theinner polymer structure and positioned within the outer polymerstructure, and (d) the outer braid; a proximal terminus of the coil isat a border between the proximal region and the overlapping region; adistal terminus of the inner braid is at the border between the proximalregion and the overlapping region; a distal terminus of the outer braidis at a border between the overlapping region and the distal region; thedistal region extends from the overlapping region to the distal portion;the distal region includes the inner polymer structure, the outerpolymer structure, and the coil wound around at least a portion of theinner polymer structure and does not include the inner braid or theouter braid; a pitch of the coil is less at a distal region of the coilthan at a proximal region of the coil.
 2. The catheter of claim 1,wherein a stiffness of the inner polymer structure decreases in a distaldirection.
 3. The catheter of claim 1, wherein a stiffness of the outerpolymer structure decreases in a distal direction.
 4. The catheter ofclaim 1, wherein the outer polymer structure has a first section havinga first stiffness and a second section distal to the first sectionhaving a second stiffness less than the first stiffness.
 5. The catheterof claim 1, wherein an outer diameter of the shaft at the distal regionis less than an outer diameter of the shaft at the overlapping region.6. The catheter of claim 1, wherein the outer polymer structure iscomposed of two different polymers.
 7. The catheter of claim 1, whereinthe outer polymer structure is composed of three different polymers. 8.The catheter of claim 1, wherein the outer polymer structure is composedof four different polymers.
 9. The catheter of claim 1, furthercomprising a handle coupled to the proximal portion of the shaft. 10.The catheter of claim 1, further comprising a liner that coats an innersurface of the inner polymer structure.
 11. The catheter of claim 1,further comprising a radiopaque marker positioned along the distalportion distal of a distal terminus of the coil.
 12. The catheter ofclaim 1, wherein the pitch of the coil varies along a length of thecoil.
 13. The catheter of claim 1, wherein the inner braid has an innerbraid pitch, and wherein the inner braid pitch is constant along alength of the inner braid.
 14. The catheter of claim 1, wherein theouter braid has an outer braid pitch, and wherein the outer braid pitchis constant along a length of the outer braid.
 15. The catheter of claim1, wherein the inner braid, the outer braid, and the coil are embeddedin the outer polymer structure.
 16. The catheter of claim 1, wherein theinner polymer structure comprises a first layer and a second layersurrounding the first layer.
 17. The catheter of claim 16, wherein thesecond layer ends proximal of a distal terminus of the coil.